1. Field of the Invention
The present invention relates to a method for clocking cumulative operating time for a cargo-handling vehicle, and the cargo-handling vehicle by use of the method.
The present invention particularly relates to the cargo-handling vehicle in which the total cumulative operating time thereof is always clocked by a clocking device on the side of the display unit (display and counter unit) of the vehicle after the shipment from the factory of the vehicle, thereby the correct total cumulative operating time can be always conserved, even when the display unit becomes out of order and is replaced by new unit.
2. Background of the Invention
A cargo-handling vehicle such as a forklift, a bulldozer, or a crane truck is used not for driving but for cargo handling in a specific area;
different from general passenger cars, the present worth of a cargo-handling vehicle depends chiefly on the cumulative operating time thereof (not on the integrating travel distance). Therefore, the cargo-handling vehicle is provided with a clocking device for clocking the cumulative operating time after the factory shipment of the vehicle. On the other hand, a passenger car is provided with an integrating travel distance meter (an odometer) for indicating how far the car has traveled since the factory shipment; in a case where the odometer become out of order and is replaced by new one, the cumulative operating time till the time point of the replacement has to be filled in the vehicle inspection certificate according to corresponding rules or regulations.
In former days, the clocking device for a cargo-handling vehicle was occasionally provided independently of a display unit for displaying the cumulative operating time; in recent times, the clocking device is often integral with the display unit. Further, the display unit itself is nowadays often treated as an assembly so that various types of data can be displayed by use of a control device with CPU and a display device with CPU, or error information and alarm information can be displayed by use of a light emitting device, for example, with LED (light emitting diodes). Contrivances are incorporated in the clocking device so that the data of the cumulative operating time in the clocking device cannot be revised after the factory shipment of the vehicle; however, in a case where the display unit is made as an assembly, the whole display unit has to be replaced by new one even when only one of the light emitting diodes becomes out order; thereby, because of the replacement with a new display unit, a problem is caused that the data as to the cumulative operating time is reset and the correct data is lost.
Further, in general, the clocking device as described above integrates the operating time while the power source for the vehicle is put under an ON-state; and, the time integration also proceeds during the adjustment before the factory shipment; therefore, the data as to the cumulative operating time is reset to zero just before the factory shipment. It is noted that resetting the data to zero is often called “0-rest” hereafter in this specification.
If the 0-reset can be performed by a user of the vehicle, there arises an apprehension that the data as to the cumulative operating time may be falsified so that it looks as if an actually long time span of a used vehicle had been a short time span. Therefore, it is a rule that the data of the cumulative operating time cannot be changed after the factory shipment of the vehicle.
In relation to the clocking device as described above, the patent reference 1 (JP2008-040568) discloses a vehicle control device by which the data regarding to the cumulative operating time cannot be altered after the factory shipment of the vehicle; thereby, the cumulative operating time is stored in a nonvolatile memory; the data (values) stored in the clocking device are made changeable by means of a tool on an external side of the clocking device (or the vehicle); the data (values) in the clocking device can be changed only when the cargo-handling vehicle is a new-vehicle; and, whether or not the vehicle is a new-vehicle is judged according to whether the cumulative operating time is zero or near zero.
According to the disclosure of the patent reference 1, the falsification of the data records after factory shipment may be prevented; however, the patent reference gives neither disclosure nor suggestion regarding how to cope with the situation in which the record of the cumulative operating time is reset to zero and becomes missing, in a case where the display device comprising the hour meter becomes out of order and has to be replaced by new one.
Further, besides the display unit as described above, a cargo-handling vehicle is provided with a plurality of functional units such as a control unit provided with a CPU performing the control over the whole cargo-handling vehicle. In a case where a user owns a plurality of the cargo-handling vehicles of the same type, one of the vehicles may sometimes go out of order; for instance, the user may experience a trouble regarding a loading/unloading function (the lift lever function) or regarding a mast inclination function (the tilt lever function). In such a trouble, the user or a service engineer practically replaces a functional unit such as the control unit for controlling the whole cargo-handling vehicle that has gone out of order, by the corresponding functional unit out of one of the other cargo-handling vehicles that are normally operated, so as to identify (isolate) the cause of the trouble, namely, so as to confine the functional unit causing the trouble. Thereby, if the malfunction is resolved by the (unit) replacement, it can be judged that the functional unit (in the disordered vehicle) before the replacement has been out of order and includes an element causing the malfunction. And, if the malfunction is not resolved by the (unit) replacement, it can be judged that the functional unit before the replacement has been under normal conditions; thus, the troubleshooting will be performed for another functional unit. In any way, after the functional unit causing the trouble is identified (isolated), the disordered functional unit is returned to the disordered cargo-handling vehicle, while the normal functional unit is returned to the normal cargo-handling vehicle; and, the vehicle with the disordered functional unit is placed under maintenance so as to repair the element causing the malfunction in the unit.
The manner of identifying the cause of a trouble by exchanging the functional units of a same type sometimes is applied to not only a well-used cargo-handling vehicle but also a relatively new cargo-handling vehicle, for instance, a cargo-handling vehicle that is placed in a showroom and encounters defective conditions due to the test rides of customers.
In view of the above-described difficulties to deal with, the subject of the present invention is to provide a method for clocking cumulative operating time for a cargo-handling vehicle and the cargo-handling vehicle by use of the method, whereby the cumulative operating time is correctly and reliably conserved under a condition that the cumulative operating time is succeeded from a functional unit to a functional unit, in a case where:                (1) a functional unit incorporated with a clocking device becomes out of order and is replaced by new one; or        (2) the functional unit incorporated with a clocking device is exchanged by an alternative functional unit so as to identify the cause of a malfunction and is returned back in-situ (to the original position of the functional unit).        
Further, the present invention aims at providing the method and the cargo-handling vehicle, whereby                (3) the data regarding the cumulative operating time can be reset to zero at the factory shipment of the vehicle, whereas the data is prevented from being falsified after the factory shipment.        